Electric soldering



2 Sheets-Sheet 1.

(No Model.)

BTHOMSQN. ELECTRIC SOLDERING.

Patented Apr. 25, 1893.

235% 7 @Wmv/n 2 N O S 0 En..A ml E ELECTRIC SOLDERING.

No. 496,019. PatentedApr. 25, 1893.

UNITED STATES PATENT OEEICE.

ELIHU THOMSON, OE LYNN, MASSACHUSETTS, ASSIGNOR TO THE THOMSON ELECTRIC WELDING COMPANY, OF MAINE.

ELECTRIC SOLDERING.

SPECIFICATION forming part of Letters Patent No. 496,019, dated April 25, 1893. Application tiled January 22, 1889. Serial No. 297,161. (No model.)

T0 all whom t may concern.: surface on which it bears, or both, or by the Be it known that I, ELIHU THOMSON, a citiinterposition of a thin septum, layer or zone zen of the United States, and a resident of of resisting material, or material modified in Lynn, in the county of Essex and State of Mascondition or form so as to oppose a resistance 5 5 5 sachusetts, have invented a certain new and to the passage of an electric current. Some useful Electric Soldering, of which the fol of these means for establishing a resistance lowing is a specification. are hereinafter more particularly described. My present invention relates to an im- In the accompanying drawingsz-Figure 1, proved method of producing soldered joints shows apparatus that may be used in prac- 6o 1o between metal pieces, and is particularly apticing my invention. Fig. 2, is a view of the plicable to soldering sheet metal pieces fiatwork. Figs. 3, 4, 5 and 6, show other forms wise. Vhen applied to tin plate the tin itself of joint and of work. Figs. 7, 8, 0, 10, 11, 12 which covers the iron plate is often sufficient and 13, are sectional, side and face views of for the uniting solder. In other cases solder clamps having particular kinds of contactl 6 5 I5 may be applied. faces. Figs. 14, 15, 16 and 17, are face and My invention consists in clamping or pressside views of elongated clamps for use in coning the pieces together at the seam or joint, nection with long joints. Fig. 1S, is a plan of passing an electric current through either or mechanism for operating an elongated clamp. both of the pieces to be joined, and in suffi- Fig. 19, is an end elevation of pressure rollers, 7o zo cient volume to melt the solder or uniting applied to the work of soldering in accordmetal, cutting off the heating electric curance with my invention. Fig. 20, is an edge rent, and maintaining the pressure until the view of a roller. Fig. 21, is an elevation of joint is sufficiently cool. l a gang of clamps and mechanism for oper- Great difficulties have hitherto been expeating the same successively and establishing 75 2 5 rienced in soldering long seams owing to the electrical connection with them in accordance fact that the cooling takes place unequally with my invention. Fig. 22, is a side elevaand, at the moment the solder sets, parts of tion of a pair of clamps the frame in which the seam contract and draw so as to break the they are mounted being shown in cross secjoint. The pressure which holds the pieces tion. 80 3o together must be continued and the piece In Fig. 1, P, P', are sheet metal pieces such held rigidly during the cooling or setting of as tin plate which are overlapped for a joint the solder. This is easily accomplished in and pressed together at the overlapped porniy invention since the cutting off of the curtion by pressure pieces C, C', one or both of rent allows the pieces toV cool, while the pieces which are movable, as C', under the influence 8 5 35 still remain clamped and held firmly during of a screw S, which, turned by a suitable the setting of the fused metal. crank or other device, gives pressure to hold My present invention, like my prior inventhe pieces P, P', firmly and squarely. The tions in electric soldering, brazing and weldpieces C, C', may be suitably guided so as to ing, involves the use of electric currents of move in a right line toward and from the 9o 4o low potential but large volume derived from other, the surfaces bearing on the overlap of any suitable source, together with suitable the plates P, P', being made true and square devices whereby the current may be cut off so as to bear evenly thereon. Heavy electric or regulated. currents are conveyed to the clamp pieces C,

My invention comprises further an im- C', by conductors K, K', or in any suitable 95 45 provement in electric soldering consisting esway from a source indicated by G. In the case sentially in establishing an electric resistance of the pieces P, P', of tin plate, a union takes to the passage of the current from the clamp place at the overlap when a sufficient strength or pressure block back of the joint to the of current to melt the tin between the surfaces metal or the work to be joined. This may has been passed. The current being then cut roo 5o be done either by modifying the surface of olf the pieces are allowed to cool in position the pressure block itself or by modifying the under pressure until thoroughly joined after which the pressure is taken off and the pieces removed. In other cases solder is applied to the joint when hot. The union is facilitated bya iiuX, if needed. Slightly oiling the melting surfaces with lard oil or other stearine containing oil will easily suffice when the pieces P, P', are tin plate.

Fig. 2, shows the pieces P, P', Iiatwise, and in dotted lines, the position of the contact clamp piece C'. The clamping devices and the means for regulating or controlling the current maybe such as are described in my prior patents Nos. 347,140, 347,141 and 347,142, or the clamping or pressure devices may be suitably modied, as to the shape of their clamping devices, when found desirable. It is not necessary in every case to pass the current across the joint from one piece to the other. rIhe current might be passed in the general direction of the line or plane of the joint.

Fig. 3, shows that the joint to be made may be a double lap instead of the single lap as in Figs. l and 2. The same application of considerable pressure, passage of soldering current and cooling under pressure with the current taken off, may be carried out with such a joint. l

Figs. 4, 5 and 6, illustrate the union of two tin plate pieces of a different form. P, is a round plate struck up into form. P', is a ring piece with one edge turned in as yindicated. The two are put together, as in Fig. 5, the pressure blocks C, C', applied to force the meeting surfaces into close and firm contact, and current is put on until the tin on the meeting surfaces melts and unites them as in Fig. 5. The blocks C, C', may be of iron or other metal, as may those of Figs. 1, 2 and 3, but to concentrate the heat in the pieces P, P', I prefer to make them of steel or iron, or copper, and face them with a facing such as hard carbon, or form their surfaces which are to be applied to the work as will be described farther on.

The facing of hard carbon F, F', Fig. 7, of the blocks C, C', Fig. 6, is for the purpose of producing an electrical resistance at the work, or where the current enters the Work, which tends to the accumulation of heat thereat with less current strength. The joint between the carbon pieces F, F' ,and the blocks C, C,should be good and made by electroplating the carbon and securing the pieces together bybrazing for example. But on account of the difficulty of this, and of the fact that the carbon is fragile, I prefer another arrangement asindicated in Figs. 8, 9, 10, 11,12 and 13. This is simply the forming of the faces of the contact and pressure blocks C, C', with notches or grooves which leave only a series of points or ridges projecting, but in a surface which will tit the work. Thus as shown in Fig. 9, a double deep set of grooves may be made crossing at an angle as indicated leaving the surface uniformly covered with raised points, or projections. In Fig. 10, a parallel set of grooves is shown cut in the surface producing a closely placed set of ridges of narrow width. In Fig. 11, the ridges are radial and formed as a consequence of the grooving being radial. In the form shown in Figs. 12 and 13, (which are respectively a face view and a side view of such a block as C, Fig. 6,) a multitude of fine wires are left to proj ect slightly from the surface of C, at F, and are ground down to a level of numerous projecting points in one plane. In all these cases the conduction of heat away from the pieces held between the blocks 1s greatly checked by the form given to the surfaces as described, and thel resistance to the passage of current at the work is increased which in itself results in further production of heat at the sheet metal pieces where pressed up together between the conducting blocks C, C'.

Figs. 14 and 15, show the grooving of the pieces at F, which are long and narrow and are used for long seams in place of those shown in Figs. 1 and 2. Fig. 16, shows the same with the two crossed sets of grooves leaving a set of points projecting from the surface.

- Fig. 17, shows the block C, of Fig. 15, 1n edge view. j

Fig. 18, shows one of the many means that may be used for securing sufficient pressure of the blocks C, C', upon-the pieces P, P', which are to be united together by current circulating in large amount from one block to the other through the work. A handle W, turns a right hand screw which is geared at- G', G", G" to two left hand screws all turning together to move the block C', toward or from stationary block C, as the need may be. The circuit connections are omitted for simplicity.

In Fig. 19, the pieces P, P', are shown as being rolled together between rollers C2, C3, connected with the source of current and whose outer surfaces are corrugated or grooved as with the pressure pieces before described. The rollers exert pressure while the current heats the thin metal pieces at successive points between the rollers. One of the rollers is shown in edge view in Fig. 20.

Fig. 21, shows how in one machine several sets of pressure pieces and current applying blocks may be successively operated, as where many pieces are to be operated upon in a given time. J to J', is a series of cams on a shaft driven by a pulley D, belted to power. The cams are set to act successively on the plunger-s C, so as to depress them successively against the action of the springs which raise them. Corresponding lower plunger-s C', insulated from the upper ones C, are arranged to be depressed in pinching or clamping the pieces between them. This is shown in Fig. 22, which is a view of one set only of the cams and plungers. I, indicates insulation about plunger C'. After pressure has been exerted to clamp the pieces the continued depression of the plunger-s by the cam S, brings the lower end of C', at a, in contact with a current feeding plate below connected with a conductor IOO IIO

K', from the current source, the other conductor K, running to the upper plungers as C. The sequence of actions then, is as followsz Pieces are placed between the plungers, pressure is applied by cams S, current passes through the pieces, when the plungers are fully depressed, current is cut olf as plungers begin to rise, and finally the pieces are released as the cam Acompletes its revolution. These actions occur respectively at different times with the dierent sets of plungers.

My present invention is especially applicable to use in uniting thin metals such as tin plates, Without solder other than the tin on the surfaces, or with solder when found desirable.

What I claim as my invention is- 1. The herein described method of producing soldered metal joints, consistingin clamping the pieces together at the seam or joint, passing an electric current through either or both the pieces to be joined and in sutiicient Volume to melt the solder or uniting material, cutting oft' the heating current,'maintaining the clamping pressure until the joint cools, and then removing the pressure.

2. rihe herein described improvement in uniting thin metal plates by a heating electric current passed through the metal and cementing material between the pieces to be united consisting in clamping the pieces between two electrodes, passing electric current from one to the other, and maintaining the clamping pressure upon the pieces after the heating current is Withdrawn and until the joint is cooled.

3. The herein described improvement in electric soldering, cementing or similar operations Which consists in passing the heating electric current into the metal of the pieces to be soldered or joined, through an artiiicial electric resistance established at the point of connection of the work with the exterior electric circuit.

Signed at Lynn, in the county of Essex and State of Massachusetts, this 18th day of J anuary, A. D. 1889.

ELIHU THOMSON.

Witnesses:

O. K. STUART, J. W. GIBBONEY. 

